U.S. Pat. No. 3,177,706 issued to Shuman et al. on Apr. 13, 1965 describes the general state of the art of spectroscopic cells for use in an industrial on-line analyzers. Such cells generally comprise a body defining a cavity therein, the body having two apertures therethrough in communication with the cavity. A window is sealed to each aperture. The cavity is filled with a fluid sample. Light is shown through one of the windows, through the sample, through the other window and then is directed to a photodetector.
A leak between the cell body and one of its windows in an industrial on-line analyzer can be a serious problem especially since such analyzers are usually not continuously attended. For example: (1) if the process stream is flammable, then there can be a fire or explosion hazard; or (2) if the process stream is toxic, then there can be a toxic release problem. It would be an advance in the art of on-stream chemical process analysis using spectroscopic cells if a cell system were developed that: (1) did not leak; or (perhaps more realistically) (2) that safely handled and detected any leak that did occur.